The present invention relates to pill or tablet counting machines. In particular, the present invention relates to counting machines which handle and dispense the pills or tablets by use of a vacuum source.
The prior art includes attempts to utilize a vacuum source to move pills within a pill counting machine; for example U.S. Pat. No. 4,018,358 to Johnston, et al (the xe2x80x9c""358 patentxe2x80x9d). The ""358 patent includes a flat disk with apertures formed along the perimeter of the disk. The disk is placed against a dish-like vacuum drive wheel and a vacuum applied to the drive wheel such that suction is created at each of the apertures in the disk. The disk is positioned such that a collection of loose pills will rest against the disk. The suction force moves pills toward and hold pills against the apertures in the disk. As the disk rotates, the pills are carried with the apertures. At some point along the rotational path of the apertures in the disk, the pills are dislodged from the aperture by a surface adjacent to the disk.
However, there are several disadvantages associated with the device disclosed in the ""358 Patent. For example, the disk is a separate piece from the drive wheel and therefore, must form at least a minimal seal along the entire perimeter of the drive wheel. Additionally, the ""358 Patent teaches the use of a continuously feeding pill cassette to position pills against its flat disk. This can result in an excessive number of pills collecting against the disk which can in turn adversely affect the consistent retention of pills on the disk""s pill apertures. To help alleviate this problem, the ""358 Patent discloses a series of spokes radially extending from the hub on which the disk rotates. The purpose of these spokes is to agitate the pills and prevent them from bridging together. However, these spokes have the undesirable tendency to chip, break, or otherwise damage the pills. Additionally, when striking pills, especially soft or uncoated pills, these spokes tend to create large amounts of dust which create a cross-contamination hazard, degrade the operation of sensors, and clog air filters associated with the vacuum source.
An effective vacuum driven pill counter which overcomes these disadvantages would be a significant improvement in the art.
The present invention provides a vacuum driven pill counter. The counter includes a counter housing with a pill discharge aperture formed therein. An integrally formed vacuum drum is rotatably positioned within the housing and the vacuum drum includes a front wall, a rear wall, and a perimeter wall. The front wall of the vacuum drum has a plurality of pill apertures formed therein. A vacuum source communicates with the housing such that the vacuum source is capable of drawing a vacuum through the pill apertures formed in the vacuum drum and a torque source is operatively connected to the vacuum drum in order to rotate the vacuum drum. A pill shelf is positioned adjacent to the front wall of the vacuum drum and a pill separator removes pills retained on the pill apertures while a pill sensor detects pills which are removed by the pill separator and exit the discharge aperture.
A second embodiment does not have an integrally formed vacuum drum, but does include a pill feeder. The pill feeder has a frame with a top and bottom aperture, with the bottom aperture being positioned over an opening in the counter housing. A pill reservoir is positioned on the frame to allow pills to flow into the top aperture of the frame. A feed gate positioned within the frame is slidably movable between the top and bottom apertures.